Voters give him a negative 39-55 percent rating on his handing of foreign policy, one of his lowest ever, and 80 percent of Americans are “very concerned” or “somewhat concerned” that the Ukraine situation could lead to a larger conflict with U.S. military involvement.

They also are divided, 42-42 percent, on who is a stronger leader — Mr. Obama or Russian President Vladimir Putin.

“Is the old Cold War Bear lurking in Ukraine? Americans express concern but caution on how to handle Russia,” said Tim Malloy, assistant director of the Quinnipiac University Poll. “It’s a tossup on who is a tougher leader, President Barack Obama or President Vladimir Putin, as Americans weigh the heavyweight standoff over Ukraine.”